Null About Smart Scenta,, Vent Clips: Smart Scent Vent Clips fill your car with true-to-life Yankee Candle fragrances. Create a welcoming mood you'll enjoy sharing with whoever's along for the ride, anywhere your journey takes you. Each Vent Clip releases rich, true-to-life fragrance for up to 30 days. Simply fasten the clip onto your car's vent, and use the clip's slider bar to adjust the fragrance strength. When the liquid disappears, it's time to replace! Fragrance Life: Up to 30 days.